Set the access rights for your map to "Edit with Login" so that registered visitors can also add events to the calendar.

In this way, shared use of different calendars is possible.

With read access rights, there is only read access to the calendar. Only the map owner can then make changes at any time.

If you share a map with “read-only rights”, the calendar will also be in read-only mode, regardless of the access rights of the map.